//
// CATGL - Cheap Action-game Tool with WebGL.
//
// Copyright 2010, tmasda.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

function FrameRate(){
    this.elem = null;
    this.table = [];
    this.lastTime = 0;
    this.maxRecord = 10;
    //this.updateInterval = 500;
    //elem:  null;
    //table: [];
    //lastTime: 0;
    //MAX_RECORD: 10;
    //UPDATE_INTERVAL: 500;
}

FrameRate.prototype.record = function(){
    if (this.lastTime == 0){
        this.lastTime = new Date().getTime();
    } else {
        var cur = new Date().getTime();
        var interval = cur - this.lastTime;
        this.lastTime = cur;
        while (this.table.length >= this.maxRecord){
            this.table.shift()
        }
        this.table.push(interval);
    }
}

FrameRate.prototype.updateCallback = function(that){
    return function() {
        var i;
        var total = 0;
        var framerate;
        for (i = 0; i < that.table.length; i++){
            total += that.table[i];
        }
        framerate = Math.round(1000/ (total / that.table.length));
        
        that.elem.innerHTML = "framerate:" + framerate + "fps";
    };
}

FrameRate.create = function(id, updateInterval){
    var fr = new FrameRate();
    fr.elem = document.getElementById(id);

    setInterval(fr.updateCallback(fr), updateInterval);
    return fr;
}
